Webster's New World Medical Dictionary

rebound
The reversal of response upon with-
drawal of a stimulus.
rebound effect
The production of increased
negative symptoms when the effect of a drug has
passed or the patient no longer responds to the
drug. If a drug produces a rebound effect, the con-
dition it was used to treat may come back even
stronger when the drug is discontinued or loses
effectiveness.
recalcitrant
Stubborn. For example, a recalcitrant
case of pneumonia stubbornly resists treatment.
recent memory
See 
memory, short-term.
receptor 1
In cell biology, a structure on the sur-
face of a cell or inside a cell that selectively receives
and binds a specific substance. For example, there
are insulin receptors and low-density lipoprotein
(LDL) receptors.
2
In neurology, the terminal of a
sensory nerve that receives and responds to stimuli.
receptor, chemokine
See 
chemokine receptor.
receptor, visual
The layer of rods and cones, the
visual cells, of the retina.
recessive
A genetic trait that appears only in indi-
viduals who have received two copies of a mutant
gene, one copy from each parent. The individuals
with a double dose of the mutated gene are called
homozygotes. Their parents, each with a single dose
of the mutated gene, appear normal and are called
heterozygotes, or gene carriers. There are two types
of recessive diseases—autosomal recessive and X-
linked recessive—that describe different patterns of
inheritance. The opposite of recessive is dominant.
See also 
autosomal recessive trait; dominant; X-
linked recessive.
recessive, autosomal
See 
autosomal recessive
trait.
recessive, X-linked
See 
X-linked recessive.
recipient
In medicine, someone who is given
something, such as a blood transfusion or an organ
transplant, that is derived from another person (the
donor).
recombinant
A person with a new combination
of genes, a combination not present in either par-
ent, due to parental recombination of those genes.